Although the most widespread opinion estimates that Donald Trump is sure to be reelected in 2020, other assessments support this.
Republicans have now an advantage of 53 against 47.
But, if there is a 50-50 equality, the vice president would break the tie.
An Associated Press (AP) journalist, Nicholas Riccardi, covering the elections believes the Democratic Party faces a geographical dilemma to win both the Senate and the White House.
He warns, this could hinder the chances to win in the upper chamber.
Besides it conditions the democratic triumph if they obtain victory in the industrial northwest, whose white working class has diminished their support.
As for the Senate, Riccardi warns, they are obliged to win the vote on what represents the future of the party.
Who? Professional sectors that reside in the suburbs, youth, and minorities.
Together, it’s estimated, they could reach a majority in the states of Arizona, Colorado, Georgia, and North Carolina.
Experts believe Democrats gained ground in the West as well in southern states, but neglected their activism in the industrial belt of the northeast.
"They are stranded between the past and the future," said William Frey, a demographer from the Brookings Institution in Washington.
In such a scenario it’s more difficult to select candidates for the Senate.
Observers associate the White House-Senate brawls with the fact that applicants seldom win a position if the presidential candidate loses in his state.
"There’s no doubt that the Sun Belt (the south) will be vital for the Democrats," said Simon Rosenberg, a spokesman for a partisan organization that demographic changes benefit the Democrats.
The latter are obliged to add four benches to reach the senatorial majority.
The far right almost celebrates Trump's success in 2020, but it would be more rational to await the development of events.